The following plugins do not display a description when you select the plugin row (in latest nightly dev build from Nov 2016):

Classic Disc Numbers
Copy Cluster to Clipboard
Disc Numbers
Feat. Artist in Titles
Feat. Artists Removed
Generate Cuesheet
Last.fm
No Release
Release Type

When you select these plugins, the previously selected plugin remains displayed - the description area is not blanked out. There are no errors in the Debug/Error log.

I suspect that this is a combination of:

a. Metadata missing from the start of the plugins; and

b. Failure of Picard code to handle missing metadata is a nice fashion.